FOR THE THIRD time in as many Congresses, the Senate is about to consider immigration reform legislation. Sen. Alan Simpson's bill designed primarily to curb the flow of illegal immigrants, had its genesis in a 1981 report of a Select Commission on Immigration and Nationality Policy whose members were appointed by the Carter administration and congressional leaders. Support for reform legislation has consistently been bipartisan, and Senate votes in favor of passage (80 to 19 in 1982 and 76 to 18 in 1983) have been large.

There is widespread agreement on the twin objectives of the bill, employer sanctions and amnesty. Father Theodore Hesburgh, chairman of the Select Commission, said these provisions were designed "to close the back door (illegal immigration) while we open the front door (legal immigration) slightly more." Both the House and Senate bills, which differ in minor respects, contain these provisions, and Attorney General Edwin Meese has testified for the administration in strong support. There are still disagreements on the details of some provisions, though: 1)the mechanics and scope of the amnesty, 2)the extent to which the federal government will assist the states in providing services for newly legalized immigrants, 3)the best means of protecting aliens from employment discrimination, and 4)the regulation of temporary agricultural workers.

Most of these differences were resolved by a conference committee last year, but time ran out before a final agreement could be hammered out. That must not happen again. The Senate should pass a bill this week, and hearings are already underway in the House. Every year this legislation is delayed the problem of an uncontrollable border grows. The Attorney General testified that the Immigration and Naturalization Service used to apprehend about 80,000 illegal immigrants a year, primarily along our southern border. That figure is now more than a million. Postponing action on the bill is also a disservice to the aliens who entered without papers, but who have been here for many years, putting down roots, raising families and contributing to our society. They want to legalize their status and eventually, to become citizens. Sen. Simpson's bill is their best hope.